Quote from: bloss on December 11, 2013, 02:00:30 PM

I'm contemplating obtaining a physical bitcoin QR code address such as this idea:
http://imgur.com/a/dHSCB
or this commercially available process:
http://www.plaquemaker.com/Titanium/Titanium-Tags.html

Before I pull the trigger on one of these kinds of solutions, I need to better understand how to use the address correctly. My understanding is that when BTC is used from an address, then the address should not be used anymore for security reasons. If that is the case, then using a single address to receive funds is confusing to me.

I prefer to use Coinbase to handle my spending BTCs. If I use a single address to receive funds within Coinbase, and that money is spent later, will the original address still be safe to use? Will Coinbase automatically handle that address safety?

Are there any other considerations I should understand before I spend money making a physical QR code address?

Thanks

Address reuse is bad for the following reasons:

- Security is lowered slightly.

- Your privacy takes a massive hit. Remember all bitcoin transactions are public information. If you reuse the same address over and over again everyone can tell how much money you are receiving and spending.

So IMO making a physical QR code is a bad idea if it encourages you to reuse addresses. And don't even think about using an address that belongs to coinbase. There are so many things that could go wrong with that. What are you going to do if coinbase shuts down? Or gets hacked? What if you need to prove ownership of the address by signing a message?

The way I see it in future the payments gateway that the bitcoin-qt team is developing will solve this problem for you. Maybe then you'll have a URL or something that you can safely share with people without loosing out on privacy.